纤维素降解菌Raoultella ornithinolytica LL1的筛选及基因组测序

Screening and Genome Sequencing of Cellulytic Bacterium Raoultella ornithinolytica LL1

纤维素作为一种资源丰富的天然聚合物,可被微生物降解为可溶性糖,因此筛选高效纤维素降解菌备受关注。本研究利用CMC选择培养基筛选出一株纤维素降解菌Raoultella ornithinolytica LL1,采用三代Pacbio Sequl和二代Illumina Novaseq平台进行基因组测序,并采用DNS法测定其纤维素酶活。R.ornithinolytica LL1基因组大小为5584354 bp,包含5512个基因,其中NR、Swiss-Prot、Pfam、COG、GO、KEGG和CAZyme数据库中分别注释有5511、4419、4584、4745、3610、3336和128个基因,同时基因组注释有大量木质纤维素降解相关基因。R.ornithinolytica LL1具有较高的纤维素酶活性,其中β-葡萄糖苷酶活性最高,其次是内切葡聚糖酶,外切葡聚糖酶活性最低。本研究通过基因组测序及酶活测定揭示了R.ornithinolytica LL1降解纤维素的能力,为其降解纤维素及进一步纤维素转化奠定了基础。

As a resource-rich natural polymer,cellulose can be degraded into soluble sugar by microorganism.Therefore,screening of efficient cellulose-degrading microorganism has attracted much attention.In the present study,CMC selective medium was used to screen a cellulose-degrading bacterium Raoultella ornithinolytica LL1.The genome sequence of R.ornithinolytica LL1 was conducted by Pacbio Sequl V3 and Illumina Novaseq platform.Furthermore,the cellulase activities of the strain were determined by DNS method.The results showed that the genome size of R.ornithinolytica LL1 was 5584354 bp and contained 5512 genes,of which 5511,4419,4584,4745,3610,3336 and 128 genes were annotated in NR,Swiss-Prot,Pfam,COG,GO,KEGG and CAZyme databases.The genes related to lignocellulose degrading in the genome were also annotated.R.ornithinolytica LL1 presented high cellulase activities,among whichβ-glucosidase showed the highest activity,followed by endoglucanase and exoglucanase.In this study,the cellulose-degrading ability of R.ornithinolytica LL1 was revealed by genome sequencing and the determination of cellulase activity,which laid a foundation for further cellulose degradation and bioconversion.